• THE DEPARTMENT• OF NATURAL• RESOURCES• miSSISSIPPI

Bureau of Geology geolo 2525 North West Street P. 0. Box 5348 Volume 9, Number 3 Jackson, Mississippi 39296-5348 March 1989

GROUND-WATER GEOCHEMISTRY AS A GUIDE TO AQUIFER INTERCONNECTION ABOVE TATUM SALT DOME, MISSISSIPPI

James A. Saunders Department of Geology and Geological Engineering University of Mississippi

ABSTRACT INTRODUCTION

Tatum Salt Dome, the site of two underground nuclear Tatum Salt Dome was the site of two underground nuclear detonations in the mid 1960's, is overlain by five semi-confined tests conducted by the U.S. Atomic Energy Commission {AEC) to confined fresh-water aquifers of Miocene age. Differential during the mid 1960's. Pre- and post-test hydrologic monitor­ head values in the aquifers indicate the potential for intera­ ing programs were established to evaluate: 1) the general quifer ground-water flow, a possibility supported by the inter· hydrogeology of the site; 2) baseline ground-water pretation of existing ground-water geochemical data. Stron­ geochemistry; and 3) the possibility of migration of ra­ tium occurs in elevated concentrations in the lowermost two dionuclides into the surrounding fresh water aquifers. Pump aquifers overlying the dome. The presence of abundant tests conducted in the aquifers over the dome have suggested celestite {SrS04) and strontianite {SrC03) in the salt dome the possibility of vertical connection between the porous salt caprock probably controls the solubility of Sr and indicates dome caprock and at least one of the overlying aquifers. that there is hydrologic communication with the lowermost Hydraulic connection between the caprock and the overly­ aquifers. Interpretation of the results of pump tests conducted ing or adjacent aquifers could potentially provide a migration by the U.S. Department of Energy supports this conclusion. path for contaminants away from the dome if leakage from In addition, these pump tests indicate some degree of the salt stock occurred. hydrologic connection between the three upper aquifers. Caprock at Tatum Dome contains abundant amounts of the Evaluation of the available ground-water geochemical data, strontium minerals celestite {SrS04) and strontianite (SrCOa), site geology, pump test results, and the general structural set­ locally up to 50% (Schlocker, 1963; Saunders, 1988; Saunders ting above this shallow salt dome indicates that faulting is the et al. , 1988). Because these minerals are not known to be most plausible mechanism of interaquifer connection. present in the aquifers, dissolved strontium provides a natural tracer to evaluate the possibility of hydraulic connection bet· T 2Nfll 1tw A' ween supradomal aquifers and the caprock. The object of the present study is to interpret available ground-water chemistry and aquifer pump test results to evaluate which aquifers may be connected. In addition, all of the available geologic logs generated from AEC drilling and earlier sulfur exploration wells of Freeport Sulphur Company were evaluated in an attempt to identity the mechanism by which the aquifers are connected. Tatum Dome is a shallow piercement salt dome that presently lies in close proximity to fresh-water Coastal Plain Soc 13 aquifers that are extensively utilized in the region. For this reason, the site hydrogeology and geochemistry provide a useful case history to consider as other salt domes are evaluated as potential repositories of low-level radioactive or chemical wastes.

GEOLOGIC AND HYDROLOGIC SETIING

-- - ( ltv Tooot S.I (t\) Tatum Salt Dome is located in Lamar County, Mississippi, --r.•-- Tooot~ (ftl approximately 22 miles southwest of Hattiesburg, within the Mississippi Salt Basin (Figure 1). The top of the caprock lies approximately 900 feet below ground surface. The dome is roughly circular in outline, and is approximately 5000 feet in Figure 1. Well locations and structural contour map showing diameter (Figure 1). The caprock of Tatum Dome is approx­ the configuration of the top of salt and caprock at Tatum Salt imately 600 feet thick over the dome crest (Figure 2) and is Dome, Mississippi. Location of geologic cross section A-A' lithologically zoned in a fashion similar to other Gulf Coast is also shown. Modified from Taylor (1964) and Saunders salt domes (e.g., Halbouty, 1979). The caprock consists of a (1988). massive anhydrite (CaSO.) zone up to 450 feet thick at the base, which is overlain by a gypsum zone 2 to 20 feet thick, saturated and is referred to as the caprock aquifer. In the vicini­ which in turn is overlain by vuggy and porous limestone up ty of Tatum Dome, the aquifers are confined and artesian. to 150 feet thick (Eargle, 1964; Saunders, 1988). The top of However, on a more regional scale, they apparently interfinger the caprock penetrates the Upper Oligocene-Miocene and coalesce to form a large interconnected aquifer system Catahoula Formation (Figure 2). The dome must have been (Taylor, 1964; Fenske, 1987). Parallel declines of water levels close to the surface during deposition of the Catahoula, of approximately 1 foot/year in aquifers 3, 2, 1, and the caprock because lignite deposits with interbedded sands and clays at Tatum Dome have occurred since the early 1960's, reflec­ up to 132 feet thick are locally present immediately above the ting the increased pumping for industrial and municipal pur­ caprock. No lignite is present in wells located away from the poses (Fenske, 1987). Fenske and Humphrey (1980) estimated dome, which indicates that the dome influenced drainage pat­ that 26.4 million gallons/day are pumped from the Miocene terns and topography locally. The Miocene Pascagoula and aquifers in the general region around Tatum Dome. The Hattiesburg formations overlie the Catahoula Formation, and regional dip of this aquifer system is approximately 40 feet have been arched at least 500 feet over the dome (Eargle, per mile to the south-southwest (e.g., Eargle, 1968). The 1968). Sand and gravel of the PliEocene Oaibome Group; aquifer 4, within 1980). a limestone unit of the Oligocene Vicksburg Group; aquifer 3B and 3A, within the Catahoula Formation; and aquifers 2B, SITE HISTORY 2A, 1, and Local aquifers within sands of the Pascagoula and Hattiesburg formations. In addition, the limestone caprock is In 1964, a 5.3 kiloton-yield nuclear device was detonated

MISSISSIPPI GEOLOGY 2 sw NE A A' • 2 3 4 5 6 1 : 8 Elevation ....._. U•l : : ~ : ~ ·~ =lll«h =1 1 ~1eat MSU , b.. I .: .I:; .,. I ... I· . Hotllo___-

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.__....,c.­_ .... · 1000 (,.) - ) .,.....,.)"=:- 8el SIOdo ~ ~--) CiiiCiini \ ~-)- \ \ \ 0 600 1000 16001 (It) \ ~ • I 260 I 0Sc .. ) I I' I

~ Figure 2. Geologic cross section A-A' through Tatum Salt Dome. Fresh-water aquifers are stippled. Modified from Taylor (1964). :%1 ~ ..... i CQ (Salmon event) in the salt stock 2710 feet below ground sur­ levels of adjacent aquifers were noted during the tests." face. The explosion produced a hemispherical-shaped cavi­ However, the drawdown in the pumped wells (Figure 3) was ty approximately 114 feet in diameter at the base, and approx­ very minor ( < 0.4 feet), suggesting that the aquifers were imately 88 feet high at the center. In 1966, a 380 ton-yield not pumped at a rate sufficient to stress the aquifers. Fenske device was detonated (Sterling event) in the cavity formed by and Humphrey (1980) presented water level data for each of the Salmon event. In addition, two non-nuclear gas explosions the aquifers (Table 1) and noted the potential for interaquifer were produced in the Salmon/Sterling cavity in 1969 and 1970 (U.S. Department of Energy, 1978). TABLE 1. WATER LEVELS IN WELLS OVER TATUM DOME Prior to the Salmon event, two deep ( > 2600 feet deep) SUMMER, 1979 hydrologic test holes, HT-1 and HT-2, were drilled approx­ imately 2000 feet away from the dome in the probable updip WELL AQUIFER ELEVATION and downdip directions, respectively (Figure 1). Pump tests (ft MSL) were conducted on each of the aquifers penetrated and HM-L L (local) 157.84 aquifer characteristics were determined. In addition, a series HT-2c L 159.11 of wells were screened in the aquifers over the dome (Figure HM-1 158.50 1): HT -4 in aquifer 1, HT-5 in aquifer 2A, HT -6 in aquifer 26, HT-4 1 161.18 and HT-7 in aquifer 3A. The results of the aquifer tests con­ HM-2a 2A 141.04 ducted on these wells are summarized by Taylor (1964): HT-5 2A 142.08 " Pumping tests at the four closely spaced wells (HT-4 through HM-2b 26 138.25 HT-7) showed hydraulic communication between the aquifers. HM-3 3A 155.27 Pumping from one aquifer caused drawdown in the water level E-7 caprock 149.78 of the other aquifers." After the Salmon event of 1964, a hole was drilled at the Reference: Fenske and Humphrey (1980). surface ground zero (SGZ) by the AEC into the cavity formed from the detonation. Drilling returns from this hole flowed in­ to an unlined mud pit, apparently resulting in the release of tritium, locally exceeding drinking water standards, into the flow based on hydraulic head differences. In addition, pump­ unsaturated zone below and the shallow unconfined "sur­ ing of each aquifer resulted in a response typical of an un­ ficial" aquifer (U.S. Department of Energy, 1978). In light of confined aquifer (Fenske and Humphrey, 1980), where the conclusion of Taylor (1964) that the supradomal aquifers delayed yield comes from gravity drainage. Figure 3 is an ex­ are hydraulically connected, the State of Mississippi requested ample of this type of response for two of the pump tests, where that additional wells be drilled into the supradomal aquifers pumping time is plotted on a log scale and drawdown on an in the vicinity of SGZ to verify that no radionuclides were be­ arithmetic scale. For a homogeneous, isotropic, non leaky, con­ ing released from the salt dome and to provide additional data fined aquifer, the drawdown-time curve should be a straight on the source of the tritium in the shallow ground water. As line as predicted from the Theis nonequilibrium condition (Fet­ a result of this request, DOE drilled a series of new wells in ter, 1988). Fenske and Humphrey (1980) proposed that depar­ 1979 designated HM-L, HM-1, HM-2a, HM-2b, HM-3 into the ture from the conventional drawdown response was due to aquifers over the dome (Figure 1). Pump tests were conducted one or more of the following: 1) aquifer leakage; 2) aquifer on the aquifers and an extensive water sampling program was consolidation; or 3) entrainment of natural gas in the water. carried out to determine the presence of any radionuclides However, because repetitions of pump tests produced the and the general water quality of each of the aquifers. Elevated same results, Fenske and Humphrey (1980) concluded that tritium values were found in the deeper Local aquifer in this aquifer leakage was the most probable cause of the observ­ study, although Fenske and Humphrey (1980) concluded that ed aquifer response, corroborating the earlier interpretation the tritium leaked from the surficial aquifer along the outer of Taylor (1964). If this conclusion is valid, then the lack of casing of one of the holes drilled in 1979. The interpretation observable water level declines in the adjacent aquifers might of data generated from this program (Fenske and Humphrey, have been a result of the low pumping rate relative to the 1980) supported the earlier interpretation of DOE that no ra­ available yield from the leaky aquifers. dionuclides are leaking from the dome into the overlying aquifers. GROUND-WATER GEOCHEMISTRY The 1979 hydrologic testing program apparently yielded dif­ ferent results than the earlier study reported by Taylor (1964). The present study was undertaken to determine if ground­ During the pumping of each supradomal aquifer, the water water geochemistry could be used to provide additional level was monitored in the other aquifers. According to Fen­ evidence of interconnection of supradomal aquifers, and to ske and Humphrey (1980): "No obvious changes in water identify which are interconnected. To that end, available water

MISSISSIPPI GEOLOGY 4 TABLE 2. GROUND-WATER GEOCHEMISTRY - TATUM DOME AREA

Over Dome Off Dome Well HM-1 HM-2A HM-2b HM-3 HT-2c HT1-1 HT1-2 HT2-2 HT1-3 HT1-4 Aquifer (1) (2A) (2B) (3A) (L) (1) (2A+B) (2A) (3A) (4) Si02 31 21 9.4 9.4 16 11 22 22 9.2 22 Fe (tot) 0.31 0.94 0.05 <0.05 1.6 0.60 1.8 1.5 0.29 0.11 Ca 11 2.2 11 12 7.5 5.2 6.2 5.4 14 5.4 Mg 1.7 0.68 1.5 0.69 1.5 0.3 1.1 1.1 1.7 2.6 Sr 0.10 0.06 0.86 2.5 0.06 NO NO NO NO NO Na 34 13 85 240 40 58 8.5 7.8 126 483 K 3.0 2.8 2.4 4.8 1.3 1.8 2.9 2.9 3.9 7.8 HC03 73 41.5 163 400 138 154 32 27 226 613 S04 10 10 61.0 29.0 10 7.4 9.6 10 99 1.4 Cl 19.2 3.8 13.8 178 4.1 4.5 4.1 4.5 21 412 F 0.2 <0.1 0.65 2.5 0.02 0.0 0.1 0.0 0.9 6.0 TDS 184 96 348 880 220 243 88 82 502 1553 Temp. 25 29 32 34 22 25 26 NO 29 33 pH 6.7 6.1 7.9 7.7 7.5 8.2 6.4 6.2 7.4 8.1 SpC 185 98 510 1120 215 261 85.3 81.4 675 28900 Date 7-79 7-79 8-79 8-79 8-79 5-61 5-61 5-61 5-61 4--61 SI-ca I -1.76 -3.21 -0.21 -0.02 -0.91 -0.30 -2.62 -2.96 -0.52 0.14 Sl-dol -3.99 -6.54 -0.85 -0.84 -2.20 -1.48 -5.63 -6.27 -1.55 0.42 Sl-cel -3.58 -3.72 -1.98 -1.96 -3.80 Sl-str -3.36 -4.35 -0.91 -0.30 -2.54 Sl-fl -2.72 -1.87 -0.77 -2.86 -3.53 -1.50 -0.46

Note: Units for dissolved species are in mg/1

Abbreviations: NO- not determined; Sl -saturation index; cal - calcite; dol- dolomite; eel -celestite; str- strontianite; fl -fluorite; SpC - specific conductance in micromhos. Reference: Data from wells over the dome from Fenske and Humphrey (1980); Off dome well data from Armstrong et al. (1961).

quality data, principally from Armstrong et al. (1 961) and Fen­ taining 465 mg/1 Ca, 1260 mg/1 S04, and lesser amounts of ske and Humphrey (1980), were compiled and interpreted in Na and Cl. No chemical data are available for aquifer 3B. light of previous hydrologic tests and the caprock mineralogy Taylor (1964) concluded that aquifers 4, 3B, and the caprock at Tatum Dome. are hydraulically connected because pumping of aquifer 3B Aquifer 5 is the deepest aquifer penetrated by hydrologic and the caprock produced water level declines in aquifer 4. test wells at Tatum Dome (Figure 2). It contains saline Na-CI All of the aquifers above the dome contain fresh Na-HCOJ ground water with approximately 18,000 mg/1 TDS at HT-2 and water (TDS < 1000 mg/1 TDS) and are of the Na-HCOJ type 11,000 mg/1 TDS at HT-1 (Taylor, 1964). This chemical dif­ typical of many Coastal Plain aquifers (e.g., Lee, 1985). ference may reflect salt dome dissolution along the path of However, aquifer 3A at HM-3 contains elevated amounts of historic ground-water flow, or increased salinity due to the chloride compared to HT-1 (178 mg/1 versus 21 mg/1), once brine injection to the southwest, or both. Aquifer 4 is brackish, again apparently indicating a salt dome mineralizing effect. with a TDS content of approximately 1550 mg/1 at HT-1. It is Another obvious difference between aquifer 3A over and away primarily a Na-HC03 type, but significant chloride is also pre­ from the dome is the higher temperature over the dome. At sent (Table 2). Analyses from aquifer 4 in HT-2 have higher HM-3, the water temperature is 34°C compared to 29°C at chloride contents than at HT-1 (up to 522 mg/1), suggesting HT-1 (Table 2), reflecting a thermal anomaly associated with some degree of salt dome - ground water interaction along the high heat flow of salt domes (e.g., O'Brien and Lerche, the probable southwesterly flow direction. No complete 1987a). In contrast, aquifer 2A at HM-2a over the dome is very analyses of water in the caprock aquifer are available, but similar to HT-2. Pumping of 2B at HT-1 produced little water Taylor (1964) described it as saline (TDS=2530 mg/1), con- and no analyses were performed exclusively on 2B off the

5 MARCH 1989 dome. An analysis from HT-1 screened in both 2A and 2B in 3A and 28. This apparent hydraulic connection is consis­ is very similar to the 2A-only analyses, indicating that either tent with the hydraulic gradient between 3A and 2B (Table 1), there was only a minor contribution from 28 or that the although seemingly at variance with a lower head reported aquifers are chemically similar away from the dome. However, for the caprock in well E-7. However, E-7 is 1800 feet south­ over the dome at HM-2b, 2B has greater pH, TOS, sulfate, southwest of HM-3, and the water level of E-7 in 1961 was chloride, sodium, and calcium contents than off the dome. identical to that for HT-7 screened in 3A at that location (Taylor, Water analyses from aquifer 1 over and off the dome are fair­ 1964). ly similar, although the pH at HM-1 , over the dome, is Water chemistry for 2A, 1, and the Local aquifer are general­ significantly lower than off the dome. ly similar both over and off the dome and are distinctly dif­ To further characterize the ground-water geochemistry in ferent than 3A and 28. This chemical difference suggests that the vicinity of Tatum Dome, the computer program WATEQF either there is no hydraulic connection between 2B and 2A (Plummer et al., 1976) was used to calculate the saturation or that any contribution from below is greatly diluted. Water indices (51) for various minerals that are important in controll­ level data (Table 1) are consistent with the former. The ing the concentrations of dissolved species. WATEQF chemical similarity of water in 2A, 1, and the Local aquifer calculates mineral saturation indices for an aqueous solution could indicate hydraulic connection between them, and the using the chemical analysis and the thermodynamic stabili­ water levels suggest a potential for downward flow between ty data for both minerals and aqueous species. The 51 is defin­ these aquifers (Table 1). ed as log (IAP/Kt), where lAP is the ion activity product from The interpretation of the water chemistry presented here the input chemical analysis, and Kt is the mineral equilibrium suggests that aquifers 3A and 2B are hydraulically connected constant at the input temperature of the solution. A solution to the caprock, whereas 2A, 1, and the Local aquifer may be that is theoretically saturated with respect to a particular interconnected but isolated from the lower aquifers in the mineral will have a 51=0; 51 is negative for undersaturation, vicinity of SGZ. Accepting this hypothesis, the following can and positive for supersaturation. For example, the analysis explain the 1979 pump tests in the vicinity of SGZ. Pumping of ground water from the limestone aquifer 4 at HT-1 (Table of aquifer 3A induced water flow from the underlying caprock; 2) has a 51 for calcite of 0.14, indicating a theoretical super­ pumping of aquifer 28 induced flow from the underlying saturation with respect to calcite. aquifer 3A and possibly the caprock; pumping of 2A induced WATEQF was used to calculate 51 values for calcite, downward flow from 1; and pumping of 1 induced flow from dolomite, celestite, strontianite, and fluorite for water analyses the Local aquifer and possibly from 2A below. However, this over the dome, and for calcite, dolomite, and fluorite where may only apply to the SGZ area, for the 1961 pump tests of the data were available for wells off the dome (Table 2). The HT -4 through HT-7 indicated hydraulic connection between 51 values for the strontium minerals are particularly useful, all of the supradomal aquifers. because the caprock aquifer contains an abundance of these minerals in addition to abundant calcite and minor amounts PROPOSED MECHANISM OF AQUIFER CONNECTION of dolomite. Unfortunately, no data are available on the Sr con­ tent of ground water in the caprock aquifer. However, using Aquifer leakage above Tatum Dome could be the result of the partial chemical analysis presented above and assum­ water supplied from the less permeable confining layers, ing saturation with respect to celestite, which is much more either directly from storage or indirectly from water supplied soluble than strontianite, WATEQF was used to estimate a Sr by the adjacent aquifer(s) above or below. However, the rapidi­ content of 22 mg/1 for the caprock aquifer. Strontium values ty and the magnitude of the departure from the ideal non­ of 2.5 and 0.86 mg/1 for aquifers 3A and 28, respectively, are equilibrium drawdown response (Figure 3) argues for a more anomalously high compared to typical ground waters in the direct connection between aquifers. Faults are exceedingly region. Skougstad and Horr (1963) analyzed more than 160 common in formations overlying salt domes (e.g. , Halbouty, samples of ground water used for public water supply in the 1979; O'Brien and Lerche, 1987b), and faulting appears to be United States for strontium. They found that 60% of the the most likely source of aquifer connection above Tatum samples contained less than the 0.2 ppm lower detection limit. Dome. Values reported for Mississippi and Louisiana ground waters It is difficult to evaluate the existence of supradomal faulting were all less than or equal to 0.2 ppm. Although the Sr con­ at Tatum Dome from the available data. Some of the arching tent of 2B is less than 3A, the 51 values for celestite are of formations over the dome shown in Figure 2 could be in­ remarkably similar, partially due to the higher sulfate content terpreted as a result of faulting. In addition, the undulation of 28. In addition, 3A and 2B are both within 1 log unit of of aquifer 1 between wells 4 and 5, and its apparent absence saturation with respect to calcite and dolomite even though in well 7, could also be caused by faulting. the host formations are sands. In an attempt to locate any potential faults over the dome, The geochemical data indicate that Sr-rich ground water the geologic logs of the nine exploration wells drilled in the migrated upward and out of the caprock and mixed with water 1940's by Freeport Sulphur Company were evaluated along

MISSISSIPPI GEOLOGY 6 probably are necessary to fully characterize the hydrogeology in this type of seHing.

011 ACKNOWLEDGMENTS I \ 0 17 ~I" An earlier version of this manuscript was greatly improved ~ \ HM-~ _,.."' "" ,.,~ 5 \ / ... - by reviews by Bill FeHer, Charles Swann, Katie Walton-Day, \ / i / and Curtis Stover. .g 0.23 \ / ~ \ I \ I ~ \ 0.28 ,_I REFERENCES CITED

Armstrong, C.A., H.B. Harris, R.E. Taylor, R.V. Chafin, and T.N. 0 3-t Shows, 1961, Log of Hydrologic Test Well1 , Tatum Dome area, Lamar County, Mississippi: Unpub. U.S. Geol. Surv. Tech. Report USGS-474-110 (Dribble 6). 0~.0~--~~--~~--~~--~~--~ I 1.0 10 100 1000 10000 Eargle, D.H ., 1962a, Geology of core hole WP-1, Tatum Dome, Tine (minutes) Lamar County, Mississippi: Unpub. U.S. Geol. Surv. Figure 3. Semilogarithmic plot of drawdown data for pump Technical Letter (Dribble 15). tests of HM-2b screened in aquifer 2B and HM-3 screened Eargle, D. H., 1962b, Geology of core hole WP-4, Tatum Dome, in aquifer 3A. Pump discharge rates are 196.8 gallons per Lamar County, Mississippi: Unpub. U.S. Geol. Surv. Tech. minute (GPM) and 192.7 GPM , respectively. From Fenske and LeHer (Dribble 19). Humphrey (1980). Eargle, D. H., 1964, Surface and subsurface stratigraphic se­ quence in southeastern Mississippi: U.S. Geol. Surv. Prof. Paper 475-D, p. D43-D47. Eargle, D.H. , 1968, Stratigraphy and structure of the Tatum with the detailed geologic logs from AEC wells WP-1 and salt dome area, southeastern Mississippi and northeastern WP-4 (Eargle, 1962a,b). The entire sequence of units above Washington Parish, Louisiana: Geol. Soc. Am. Sp. Paper the dome consists predominantly of alternating sands and 88, p. 381-405. clay, and precise correlation between wells was not possible Fenske, P.R. , and T.M. Humphrey, Jr., 1980, The Tatum dome from the available data. However, the presence of lignite over project, Lamar County, Mississippi: U.S. Depart. of Energy­ the dome provides a useful and easily recognizable marker Nevada Oper. Office NV0-225, 134 p. horizon. A sequence of lignite interbedded with sands and Fenske, P.R., 1987, Miocene groundwater overdraft in southern clays reaches a maximum observed thickness of 132 feet at Mississippi, in Hawkins, E.J. (ed.), Proc. 17th Miss. Water a depth of 784-916 feet in WP-4 (Eargle, 1962b) and is ab­ Resources Cont., Jackson, Miss., p. 83-87. sent from WP-1 approximately 1500 feet to the west-northwest. FeHer, C.W., 1988, Applied Hydrogeology (2nd ed.): Merrill Eargle (1962b) stated " the consptcuous differences between Publishing Co. , Columbus, OH, 592 p. the sections immediately above the caprock in the two holes Halbouty, M.F., 1979, Salt domes, Gulf region, United States are most probably due to faulting followed by erosion ..." and Mexico: Gulf Publishing Company, Houston. Lignite was encountered in four of the Freeport holes, but ab­ Lee, R.W., 1985, Geochemistry of groundwater in Cretaceous sent in the remainder, providing further support for Eargle's sediments of the southeastern Coastal Plain of eastern conclusion about faulting. Mississippi and western Alabama: Water Resour: Res., v. 21, p. 1545-1556. CONCLUSIONS O'Brien, J.J., and I. Lerche, 1987a, Heat flow and thermal maturation near salt diapirs, in J.J. O'Brien and I. Lerche The combined geochemical, hydrologic, and geologic data (ads.), Dynamical Geology of Salt and Related Structures: support the conclusion that aquifers above Tatum Dome are Academic Press, Austin, Texas, p. 711-750. interconnected by faults to varying extents. At SGZ, the O'Brien, J.D., and I. Lerche, 1987b, Modelling of the defor­ caprock, 3A, and 2B aquifers are connected but separated mation and faulting of formations overlying an uprising salt from the overlying, apparently interconnected, 2A, 1, and dome, in J.J. O'Brien and I. Lerche (eds.), Dynamical Local aquifers. However, 1800 feet south-southwest of SGZ, Geology of Salt and Related Structures: Academic Press, all of the aquifers may be connected. These interpretations Austin, Texas, p. 419-455. suggest that aquifer-fault relationships ir'l the three dimensions Plummer, LN., B. F. Jones, and A. H. Truesdell, 1976, WATEQF­ are complex, as would be expected over the crest of a shallow a FORTRAN IV version of WATEQ, a computer program salt dome. That being the case, additional hydrologic tests for calculating chemical equilibrium of natural waters: U.S.

7 MARCH 1989 Geol. Surv. Water Resour. Invest. 7~13, (rev. 1984). Tech. Letter (Dribble 28). Saunders, J.A., 1988, Lead-zinc-strontium mineralization in Skougstad, M.W., and C.A. Horr, 1963, Occurrence and limestone caprock from Tatum salt dome, Mississippi: Gulf distribution of strontium in natural waters: U.S. Geol. Surv. Coast Assoc. Geol. Soc., Transactions, v. 38, p. 569-576. Water Supply Paper 1496-D, p. D55-D97. Saunders, J.A., J.D. Prikryl, and H.H . Posey, 1988, Mineralogic Taylor, A.E. , 1964, Geohydrology of Tatum salt dome area, and isotopic constraints on the orig in of strontium-rich Lamar and Marion Counties, Mississippi: Unpub. U.S. caprock, Tatum Dome, Mississippi, U.S.A.: Chemical Geol. Surv. Tech. R~pt. VUF-1023. Geology, v. 74, p. 137-152. U.S. Department of Energy, 1978, Special Study, Tatum Dome Schlocker, J., 1963, Petrology and mineralogy of Tatum salt test site, Lamar County, Mississippi: U.S. Department of dome, Lamar County, Mississippi: Unpub. U.S. Geol. Surv. Energy, Nevada Operations Off., NV0-200.

NEW PUBLICATION BY THE BUREAU OF GEOLOGY

PRELIMINARY EVALUATION OF COAL AND COALBED GAS RESOURCE POTENTIAL OF WESTERN CLAY COUNTY, MISSISSIPPI

The Bureau of Geology announces the publication of bituminous coal resources in excess of 5.2 billion tons at Report of Investigations 1, "Preliminary Evaluation of Coal depths shallower than 3700 feet. Using the somewhat con­ and Coalbed Gas Resouce Potential of Western Clay Coun­ servative estimate of 200 cubic feet of gas per ton of coal, ty, Mississippi," by Kevin S. Henderson and Conrad A. the total coalbed gas reserves are estimated to exceed one Gazzier. trillion cubic feet of gas. This publication describes an investigation of Pottsville For- . Report of Investigations 1 may be purchased from the mation coalbed gas resources of western Clay County, Bureau of Geology at 2525 North West Street, Jackson, for Mississippi. The study documented the presence of four coal $5.00 per copy. Mail orders will be accepted when accom­ groups within 3700 feet of the surface. These four groups con­ panied by payment ($5.00, plus $1.50 postage and handling). sist of as many as 17 individual seams with thicknesses vary­ Address mail orders to: ing from two to six feet. Aggregate thicknesses of all coal Bureau of Geology seams in these four groups may exceed 25 feet, with 16 feet P. 0. Box 5348 being the average. It is estimated that the study area has Jackson, MS 39296

MISSISSIPPI GEOLOGY 8 FOSSIL PALM STEM FROM BAYOU PIERRE, COPIAH/CLAIBORNE COUNTIES, MISSISSIPPI

Will H. Blackwell Department of Botany Miami University Oxford, Ohio 45056

INTRODUCTION presented his study of the "flora" of the Catahoula Sandstone, examined from outcrop (or outwash from outcrop) in Mississip­ In a survey of fossil (silicified) wood occurring in the Bayou pi, Louisiana, and Texas. Berry recognized a total of seven Pierre drainage, Copiah and Claiborne counties, Blackwell species of Palmoxylon, all previously described: viz., P. and others (1983) reported a variety of woods, including ovatum, P. mississippense, P. texense, P. lacunosum, P. predominantly dicotyledonous woods, but with some con­ cellulosum, P. remotum, and P. microxylon. These species iferous woods and also fossil palm being found. In contrast were distinguished, as viewed in microscopic cross-section, to the majority of the dicot and conifer petrifactions (these con­ by technical features of or relating to the fibrovascular bundles, sidered to be associated with Pleistocene pre-loess terrace the auxiliary sclerenchyma bundles (i.e. , those possessing gravels), the fossil palm was interpreted as having a probable fibers but not vascular tissue), and ground tissue features derivation from the Oligo-Miocene Catahoula Formation, (e.g., ground tissue "expanded" and hence showing in­ through which the Bayou Pierre drainage cuts. Specimens tercellular space, or else not so). Of these species, Berry listed (large and small) of the silicified palm, found mixed with the the occurrence of only P. cellulosum from Bayou Pierre, a fossil dicot and conifer woods, were interpreted as being species lacking auxiliary bundles; Palmoxylon cellulosum had reworked by stream action into the Pleistocene gravel been previously described by Knowlton (1888) from Rapides deposits. The inclusion of palm in our paper (1983) was bas­ Parish, Louisiana. Berry did, however, indicate the occurrence ed on several specimens collected personally and on a larger of other species of Palmoxylon from Mississippi, including P. collection of specimens from the vicinity (Copiah/Ciaiborne ovatum, from Adams County. Palmoxylon ovatum had been County line) donated to the authors by the Schabilion family described (from Mississippi) by Stenzel in his masterful of the Mississippi Petrified Forest at Flora, Mississippi. In monograph of fossil palms published in 1904. essence, the occurrence of fossil palm was simply listed in the paper, and designated by the rather generalized descrip­ RESULTS AND DISCUSSION OF CLASSIFICATION tor, Palmoxylon. Subsequently, Blackwell (1984) presented information on Sectioning of the Bayou Pierre specimens available to me the Bayou Pierre material regarding means of determining, personally (including the Schabilion collection) did not reveal for fossil palm specimens found, the possible horizontal and a form definitely comparable to Palmoxy/on cel/ulosum. vertical positions which they originally occupied in the stem However, material quite comparable toP. ovatum and also to of the once-living palm; information was also presented to P. /acunosum (Unger) Felix (1883) was discovered (Figures assist in deciding with assurance whether or not petrified stem 1-6). Palmoxylon /acunosum (Figures 1-4), listed by Berry material discovered is in fact fossil palm (aided by Tomlinson, (1916) from Rapides Parish, Louisiana, is distinguished from 1961, and Tomlinson, personal communication), as opposed P. cellulosum by the presence (in lacunosum) of auxiliary to belonging to some other plant group (including other groups (fibrous only) bundles, and perhaps by a greater percentage of monocots). It should be realized by the reader that palm of vascular tissue in the fibrovascular bundles. Palmoxy/on "wood" is not truly wood (which is secondary vascular tissue), ovatum is distinguished from either (/acunosum or ce/lulosum) but is composed of a variety of tissues, the cells of which are by a ground tissue lacking intercellular space (composed as totally of primary origin - very much comparable to the stem it is of more or less isodiametric cells) and by apparently tissues of a corn plant (see Tomlinson, 1967). unitary fibrous strands (appearing as dark dots in photograph, At the present time, it is possible in light of historical studies Figures 5-6) - as opposed to either the presence of compound to make cautious statements regarding the classification fibrous bundles or else the total lack of such bundles. (perhaps even the "systematic relationships") of fossil palm Since this writer has no reason to doubt Berry's determina­ stem material found at Bayou Pierre. The study of fossil palm tion of P. cellulosum, the determination being a relatively clear­ from Bayou Pierre (and elsewhere in the Southeast) has a cut matter, at least three species of fossil palm (P. cellulosum, long though decidedly intermittent history. In 1916, Berry P. ovatum, and P. lacunosum) seemingly occur in the Bayou

9 MARCH 1989 Pierre drainage (and the ultimate discovery of additional forms types typically presents no real problem. It is only when one would not be surprising). In collections available to me, attempts a much more precise identification, i.e., a true com­ specimens identifiable as P. lacunosum were found to be com­ parison to extant taxa, that great difficulty is encountered. mon. The question of correspondence of any or all of these In consideration of various features, including reasonably fossil palm species to extant palms Is a difficult one to answer. abundant fibrous (auxiliary) bundles in the stem periphery Tomlinson (personal communication) cautions as to the un­ (Figures 1-2), material classified as P. lacunosum is not in­ profitability of equating most fossil palm stem section material consistent with the modem "coryphoid" genus Washingtonia, with that of extant genera and spec1es of palms. In spite of a desert fan palm with two species found today in western a great deal of recent work on palm taxonomy (e.g., Uhland Arizona, southeastern California, and parts of northwestern Dransfield, 1987), the systematic anatomy of palms remains Mexico. Based on a ground tissue lacking expansion, and sim­ clouded. The uncertainty of meaning, taxonomically, of much ple fibrous strands (dark dots, as seen in cross-section, palm structural material relates to the potentially great inter­ Figures 5-6), P. ovatum is generally comparable to stem nal anatomical variability of palm stems of various types, both material of Cocos nucifera (coconut palm). However, these vertically and horizontally (Kaul, 1960; Tomlinson, 1961; statements are not to be construed as determinations of the Mahabale, 1966) as well as to difficulties in sectioning (Kaul, true identity of P. lacunosum and P. ovatum, respectively, but 1960; Tomlinson , 1967). Reliable patterns of stem anatomy rather only as tentative suggestions of similarity to extant (especially ground tissue or " expanded" ground tissue pat­ forms. It is even more difficult to suggest what P. cel/ulosum terns), if present at all, are to be sought in the very mature could possibly be, especially since I have not directly observed stem (Schoute, 1912; Kaul, 1960), i.e., toward the stem base. any specimens of this taxon. However, the modem coryphoid Because of the tropical location (inaccessibility) of most palms, genus Saba/ might be considered as a possibility for even­ and difficulties of obtaining tissue from the internal stem base tual comparison, based on the absence of fibrous bundles even when field access to palms is gained, suitable com­ in this genus (as opposed to the presence of such in parative extant anatomical material is often not available. Washingtonia). Quite circumstantially, Berry (1916) did report In spite of the above pessimism, it is feasible to make some leaf material of Sabalites from the Catahoula " flora." suggestions as to the classification and even the relationships As alluded to earlier, it is possible to assess characteristics of specimens of petrified palm stems. In general, an artificial of petrified palm stem specimens, related but additional to but nonetheless useful classification of palm stem material their taxonomy. If, for example, one exam1nes the photographs into three general categories, based on cross-sectional ap­ of P. lacunosum, it is perceivable, based on spacing of pearance, has been employed (Stenzel, 1904; Kaul, 1960; vascular bundles and relative expansion of ground tissue, that Sahni, 1964). These three categories are named broadly after the specimen represented in Figure 4 is probably from a more palm genera considered representative of each of the inner portion (position) of the stem than is the specimen il­ categories; these are, Mauritia-like, Corypha-like, and Cocos­ lustrated in Figure 1. In this regard, Kaul (1 960) presents a like stem cross-sectional appearances. Of the three, Mauritia­ helpful account of characteristics of different horizontal regions like stems are uncommon compared to the other two types of a palm stem. Furthermore, the thickened walls of the fibers (see Sahni, 1964). Based on fi brovascular bundle distribution of the fibrovascular bundle seen in Figure 3 suggest that th1s and configuration, and ground tissue expansion (appearance), specimen came from the base (very mature portion) of the P. lacunosum and P. cel/u/osum would be considered definitely stem (Tomlinson, personal communication). Hence, features " Corypha-like," and P. ovatum would be "Cocos-like." observable in fossil stem pieces (specimens) may provide in­ Categorization of fossil palm stem sp-9Cimens found at Bayou formation as to the initial horizontal and vertical position of Pierre (and elsewhere) Into one or more of these three general occurrence of these specimens in the once living palm trunk.

Legend for Figures

Figures 1-4, Palmoxylon lacunosum: (1) Cross-section through stem sample probably originating from outer region of fossil palm trunk (X 30); note rather closely spaced vascular (fibrovascular) bundles (one featured immediately to the left of the number one), ground tissue with limited air spaces (center-lett), and auxiliary (fibrous only) bundles (one pointed out with arrow). (2) Auxiliary (sclerenchyma) bundle enlarged (X 260). (3) One vascular bundle enlarged (X 85); note large region (dark area to right) of fibers, each fiber showing a thickened wall; two large metaxylem vessels are evident to lett in the bundle. (4) Cross­ sectional area of specimen probably originating toward center of fossil palm trunk (X 12); note regular air spaces formed in "expanded" ground tissue between and around the more widely spaced vascular bundles. Figures 5-6, Pa/moxylon ovatum: (5) Cross-section of sample (X 30) demonstrating the lack of air spaces in the ground tissue (composed of more or less isodiametric cells) and the unitary fibrous strands (dark dots). (6) Unitary fibrous strand (arrow) enlarged (X 260); note definitive border around strand.

MISSISSIPPI GEOLOGY 10 11 MARCH 1989 GEOLOGICAL ASSOCIATION REFERENCES CITED

Of the possible formations from which the fossil palm Berry, E.W., 1916, The flora of the Catahoula Sandstone: U.S. material could be associated in the Bayou Pierre drainage Geological Survey, Professional Paper 98, p. 227-252. in Copiah and Claiborne counties, the only plausible choices Bicker, A.A., Jr., T.H. Dinkins, Jr. , C.H. Williams, Jr., and T.E. seem to be either the pre-loess terraces (gravels) of McCutcheon , 1966, Claiborne County geology and mineral Pleistocene age, or else the Oligocene or Miocene (depen­ resources: Mississippi Geological, Economic and ding on interpretation) age Catahoula Formation (Matson, Topographical Survey, Bulletin 107, 174 p. 1916; Bicker and others, 1966, 1969). As in our 1983 paper Bicker, A.A., Jr., T.N. Shows, T.H. Dinkins, Jr., and T.E. McCut­ (Blackwell et al.}, we still favor an interpretation of associa­ cheon, 1969, Copiah County geology and mineral tion of fossil palm material with the Catahoula Sandstone. resources: Mississippi Geological, Economic and Reasons for favoring an Oligo-Miocene (vs. Pleistocene) age Topographical Survey, Bulletin 110, 172 p. for the palms include: 1) Berry (1916) was able to relate all Blackwell, W.H., and G.H. Dukes, 1981, Fossil wood from species of palms recognized in his manuscript, from Thompson Creek, Yazoo County, Mississippi: Mississippi Mississippi to Texas, to the Oligo-Miocene Catahoula Forma­ Geology, v. 2, no. 2, p. 1-6. tion. 2) Stenzel (1904) considered Palmoxylon ovatum to be Blackwell, W.H. , M.J. Powell and G.H. Dukes, 1983, Fossil related to a species of fossil palm described from the Lower wood from Bayou Pierre and White Oak Creek, Southwest­ Oligocene or Upper Eocene of Libya. 3) Fossil palm is Central Mississippi: Mississippi Geology, v. 4, no. 2, p. 1-6. reported in geological horizons from the Upper Cretaceous Blackwell, W.H. , 1984, Palmoxylon from Bayou Pierre, to the Pliocene (see Mahabale, 1958; Kaul, 1960; Sahni, 1964; Copiah/Ciaiborne County line, southwestern Mississippi: Daghlian, 1981). Authentic Pleistocene reports are apparent­ American Journal of Botany, v. 71, no. 5, pt. 2, p. 113. ly lacking; however, potential (eventually discovered) (published abstract) Pleistocene occurrences cannot be ruled out (since, after all, Daghlian, C.P., 1981, A review of the fossil record of palms are very much with us in the present day). 4) The very Monocotyledons: The Botanical Review, v. 47, no. 4, p. tentative determination of Palmoxylon ovatum as "Cocos-like" 517-555. would, if correct, be indicative of plants inhabiting a marine Dockery, D.T., Ill, 1987, Petrified palm " wood" from Thomp­ borderland environment. This environment would be more son Creek, Yazoo County, Mississippi: Mississippi Geology, consistent with conditions possibly existing in the Oligocene v. 8, no. 2, p. 10-11. or early Miocene environment of Copiah/Ciaiborne counties, Felix, J., 1883, Die fossilen holzer Westindiens: Samml. than with Pleistocene (even Pleistocene interglacial) condi­ Palaont. Abhandl., Ser. 1, Heft 1, p. 22-27. tions there. In this connection, Berry (1916) considered the Kaul, K.N., 1960, The anatomy of the stem of palms and the Catahoula "flora" in general to have coastal-tropical rather problem of the artificial genus Palmoxylon Schenk: than "upland" or "inland" affinities. 5) Fossil palm, common Bulletin, National Botanic Gardens, Lucknow, India, v. 51, at Bayou Pierre, is not common (Dockery, 1987) in similar p. 1-52. Pleistocene drainages (Pleistocene gravels) in Mississippi Knowlton, F.H., 1888, Description of two species of (such as Thompson Creek) located to the north of Bayou Palmoxylon-one new-from Louisiana: Proceedings of Pierre; yet dicot and even coniferous wood is common in these United States National Museum, v. 11, p. 89-91 . drainages as it also is at Bayou Pierre (Blackwell and Dukes, Mahabale, T.S., 1958, Resolution of the artificial palm genus, 1981; Blackwell and others, 1983). Thus, a potentially different Palmoxylon-a new approach: The Palaeobotanist, v. 7, p. (non-Pleistocene) source for the Bayou Pierre palm would 76-84. seem to be indicated. 6) Very subjectively, specimens of fossil Mahabale, T.S., 1966, Evolutionary trends in the Pal mae with palm examined typically bear a similarity in appearance to special reference to fossil palms: The Palaeobotanist, v. weathered chunks of the Catahoula Sandstone; whereas, the 14, p. 214-222. fossil dicot and coniferous material is quite diverse in ap­ Matson, G.C. , 1916, The Catahoula sandstone: U.S. Geological pearance, and generally similar to that in the Thompson Creek Survey, Professional Paper 98, p. 209-226. drainage, for example. 7) I found one specimen of fossil palm Sahni, B., 1964, Revisions of Indian fossil plants, part Ill­ immediately adjacent to and apparently weathered from an Monocotyledons: Monographs of the Birbal Sahni Institute outcrop of the Catahoula at Bayou Pierre; however, it was not of Palaeobotany, Lucknow, no. 1, 89 p. (plus plates). possible to make a definite connection in that case. To answer Schoute, J.C. , 1912, Uber das dickenwachstum der palmen: the question of the probable association of the Bayou Pierre Ann. Jard. Bot. Buitenzorg, Ser. 2, v. 11, p. 1-209. palm material with the Catahoula Formation conclusively, pro­ Stenzel, K.G., 1904, Fossile palmenholzer: Beitrage zur fessional and amateur collectors alike should be encourag­ Palaont. und Geol. Ost.-Ungarns und des Orients, Band ed to be on the lookout for any specimen of fossil palm still 16, p. 107-287 (plus plates). possibly occurring in place in the Catahoula Sandstone. Tomlinson, P.B., 1961, Anatomy of the Monocotyledons II ,

MISSISSIPPI GEOLOGY 12 Palmae: Lo.ndon, Oxford at the Clarendon Press. Anatomists, v. 2, p. 4-24. Tomlinson, P.B., 1967, The "wood" of Monocotyledons: Uhl, N.W., and J. Dransfield, 1987, Genera Palmarum: Bulletin of the International Association of Wood Lawrence, Kansas, Allen Press, 610 p.

The search for knowledge is the noblest endeavor of mankind. The great strength of mind that has fueled men in the enter­ prise of science must never be diminished by any special definition of its goals. There Is only one science and that is basic science. This means we must look at what Is there to see and what the universe is about - piloting In uncharted waters, exploring, and learning. Kevin C. Spencer 1987

Knowledge is unique in that it is our only resource that in­ creases with use - the more we use it, the more we have. Dixy Lee Ray 1989

13 MARCH 1989 MISSISSIPPI PLACE-NAMES TRIVIA

Michael B.E. Bograd Mississippi Bureau of Geology

One interesting aspect of work at the Bureau of Geology Table 1. Places In County of Same Name is dealing with curious place-names. Many names come to light during our routine work throughout the state; others are Attala (now Kosciusko) spotted on old maps or on the hundreds of topographic maps Bolivar we stock for sale. Still other names come to our attention when Carroll visitors inquire about names of obscure places, both extant Coahoma and extinct. Franklin (now Meadville) Sources of information about place-names include Brieger Grenada (1980), topographic maps published by the U.S. Geological Lauderdale Survey, a card file at the Mississippi Department of Archives Madison and History, several articles (Gannett, 1902; Phelps and Ross. Nashoba 1952; and Mauney, 1985), and numerous articles in the state's Newton newspapers. Panola (extinct) This article addresses just one aspect of place-names trivia Pontotoc - a comparison of town names with Mississippi counties of Rankin the same name. Table 1 is a list of places that are found in Sunflower the county of the same name (e.g., the town of Newton is in Tishomingo Newton County). Table 2 is the same thing, but the town Tunica names are some variation of the county name (e.g .• Calhoun Wilkinson City is in Calhoun County). Table 3 is a list of places that share Winston(?) a name with a Mississippi county but are located in another county (e.g., places called Smith are located in Covington, Lauderdale, Newton, and Pearl River counties, but not in Smith County). Table 4 is the same as Table 3, but with spell­ Table 2. Places In County of Same Name (Variations) ing variations. Attalaville (extinct) REFERENCES CITED Calhoun City Carrollton Brieger, J.F., 1980, Hometown Mississippi, 2nd edition: private­ Chickasaw Switch ly published, 557 p. East Lincoln Gannett, H., 1902, The origin of certain place names in the Lafayette Springs State of Mississippi: Publications of the Mississippi Leakesville (now Carthage) Historical Society, v. 6, p. 339-349. Madisonville (extinct) Mauney, J.L., 1985, What's in a name?: Mississippi Magazine, North Carrollton v. 3, no. 5, p. 9-12. Union Hill Phelps, D.A., and E.H. Ross, 1952, Names please: place­ Warrenton names along the Natchez Trace: Journal of Mississippi Waynesboro History, v. 14, no. 4, p. 217-256. West Lincoln Yazoo Junction (extinct) Yazoo City

MISSISSIPPI GEOLOGY 14 Table 3. Places In County of Different Name Union (now Friar's Point), Coahoma Co. Union, Greene Co. Adams (extinct), Pearl River Co. Union, Jones Co. Adams, Hinds Co. Union, Lee Co. Alcorn. Claiborne Co. Union, Newton Co. Benton, Yazoo Co. Walthall (Gatewood), Yalobusha Co. Calhoun, Jones Co. Walthall, Webster Co. Calhoun , Newton Co. Washington (now Neely), Greene Co. Calhoun , Winston Co. Washington, Adams Co. Choctaw, Bolivar Co. Webster, Winston Co. Choctaw, Holmes Co. Wilkinson (extinct), Lincoln Co. Claiborne, Hancock Co. Yalobusha, Leflore Co. - named for river Clay, ltawamba Co. DeSoto, Clarke Co. Forrest, Attala Co. Franklin, Holmes Co. Table 4. Places In County of Different Name (Variations) George (extinct), Rankin Co. George, Yazoo Co. Calhoun Station (now Gluckstadt), Madison Co. Humphreys (extinct), Claiborne Co. Carrollville (extinct), Prentiss Co. lssaquena, Sharkey Co. Clayton, Tunica Co. Jackson, Hinds Co. Claytown, Winston Co. Jefferson (now Hernando), DeSoto Co. Forreston (extinct), Lowndes Co. Jefferson, Carroll Co. Georgetown, Copiah Co. Jones (now Gift), Alcorn Co. Georgeville (extinct), Holmes Co. Jones, Chickasaw Co. Grenada Junction (extinct), Leflore Co. Lamar, Benton Co. Holmesville, Pike Co. Lawrence, Newton Co. lttawamba (extinct), Marshall Co. Lee (extinct), Bolivar Co. Jackson Landing, Pearl River Co. Lee (extinct), Jefferson Davis Co. Jackson Springs (extinct), Lauderdale Co. Leflore, Grenada Co. Jackson's Point (extinct), Coahoma Co. Marion, Lauderdale Co. Jacksonville (extinct), Kemper Co. Monroe (now Maybank), Forrest Co. Jones Crossing, Holmes Co. Monroe, Franklin Co. Jones Mill, Harrison Co. Montgomery (now Pickens), Holmes Co. Jonesboro (now Chalybeate), nppah Co. Montgomery, Holmes Co. Jonestown, Coahoma Co. Montgomery, Lincoln Co. Jonestown, Warren Co. Perry (extinct), Stone Co. Leake's Switch (extinct), Covington Co. Prentiss (extinct), Bolivar Co. Leakesville, Greene Co. Prentiss, Jefferson Davis Co. Marion Landing (now Sidon), Leflore Co. Quitman, Clarke Co. Newtonville (extinct), Attala Co. Rankin, Holmes Co. North Union, Attala Co. Scott, Bolivar Co. Old Union, Lee Co. Sharkey, Tallahatchie Co. Perryville (now Bryant), Yalobusha Co. Smith, Covington Co. Pikeville (now Egypt), Chickasaw Co. Smith, Lauderdale Co. Piketon, Scott Co. Smith, Newton Co. Sunflower Landing (extinct), Coahoma Co. Smith, Pearl River Co. Union Church, Jefferson Co. Stone (extinct), Neshoba Co. Union Hall, Lincoln Co. Stone or Stone's Switch (extinct), Chickasaw Co. Uniontown (extinct), Jefferson Co. Stone, Panola Co. West Union, Attala Co. Tallahatchie (extinct), Panola Co. - named for river Winstonville, Bolivar Co. Tate (extinct), Pearl River Co. Yazoo Pass (now Rich), Coahoma Co. Union (extinct), Simpson Co.

15 MARCH 1989 MISSISSIPPI GEOLOGY Department of Nlltural Resources Bur.. u of Geology Post Offlc. Box 5348 Jacuon, Mlaalaalppl 39296-5348

Mississippi Geology Is published quarterly In March, June, September and December by the Mississippi Department of Natural Resources, Bureau of Geology. Contents include research articles pertaining to Mississippi geology, news Items, reviews, and listings of recent geologic literature. Readers are urged to submit letters to the editor and research articles to be considered tor publication; format speclftcatlons will be forwarded on request. For a free subscription or to submit an article, write to:

Editor, Mississippi Geology Bureau of Geology Editors: Michael B. E. Bograd and David Dockery P. 0. Box 5348 Jackson, Mississippi 39296-5348